Abstract: A process for preparing fine fibers (or whiskers) consisting of carbon and silicon is disclosed, in which a mixed gas of transition metal compound(s), organo-silicon compound(s) and optionally carbon compound(s) is reacted at a high temperature, such as in the range of 700.degree. to 1,450.degree. C.

Abstract: An alumina-carbon shape is manufactured from a composition comprising 1-8 weight percent fine silicon, 1-16 weight percent reactive alumina, 1-30 weight percent calcined fluidized bed coke, 1-30 weight percent of a spalling inhibiting additive, and the balance of the mix synthetic alumina, plus the additions of 5-10 weight percent of a high carbon yielding resin as a molding vehicle and 0.5-4 weight percent solvent, and up to 2 weight percent of a low temperature curing agent, such as, paraformaldehyde or hydrochloric acid. The mix is formed at ambient temperature into a shape through an injection molding process. Solidification is accomplished by curing in the mold at a temperature less than 100.degree. C. After stripping the shape from the mold, the solvents are removed from the shape by drying at a temperature above 100.degree. C. The shapes are then heated to a temperature above 550.degree. C. to coke the resin.

Abstract: Porous silicon carbide bodies are obtained by starting with a powder of particle size falling within a single sieve mesh range fraction and consisting either entirely of carbon particles or a mixture of carbon and silicon carbide particles of the same mesh fraction is mixed or coated with 15 to 30% by weight of a binder, moulded to shape, warmed in the temperature range from 40.degree. to 200.degree. C. to vaporize volatile material and then coked at a temperature rising to 850.degree. C. Then it is siliconized by raising the temperature to the range from 1650.degree. to 1950.degree. C. with gaseous silicon or impregnated with silicon by dipping the body into a silicon melt and convert it to carbide, with the excess silicon thereafter being removed by vaporizing out or by boiling in lye. Sieve mesh fractions in the region of a few hundred .mu.m are preferred, and the density of the porous body after pressing but before siliconizing should lie in the neighborhood of 0.6 to 0.7 g/cm.sup.3.

Abstract: One aspect of the present invention relates to methods for the continuous production of silicon carbide and other carbide and refractory products by fluidized bed techniques, the apparatus for such continuous production, and the carbide products produced therefrom being further aspects of the present invention.

Abstract: Finely divided silicon carbide containing at least 10% by weight of 2H-type silicon carbide is very easily sinterable and can be sintered into a sintered body having a density of at least 85% of the theoretical density by sintering or a hot pressing at a temperature lower than the sintering temperature of ordinary .beta.-type submicron silicon carbide.

Abstract: A method of producing articles comprising reaction-bonded silicon carbide (SiC) and graphite (and/or carbon) is given. The process converts the graphite (and/or carbon) in situ to SiC, thus providing the capability of economically obtaining articles made up wholly or partially of SiC having any size and shape in which graphite (and/or carbon) can be found or made. When the produced articles are made of an inner graphite (and/or carbon) substrate to which SiC is reaction bonded, these articles distinguish SiC-coated graphite articles found in the prior art by the feature of a strong bond having a gradual (as opposed to a sharply defined) interface which extends over a distance of mils. A method for forming SiC whisker-reinforced ceramic matrices is also given. The whisker-reinforced articles comprise SiC whiskers which substantially retain their structural integrity.

Abstract: A method whereby silicon carbide-bonded SiC fiber composites are prepared from carbon-bonded C fiber composites is disclosed. Carbon-bonded C fiber composite material is treated with gaseous silicon monoxide generated from the reaction of a mixture of colloidal silica and carbon black at an elevated temperature in an argon atmosphere. The carbon in the carbon bond and fiber is thus chemically converted to SiC resulting in a silicon carbide-bonded SiC fiber composite that can be used for fabricating dense, high-strength high-toughness SiC composites or as thermal insulating materials in oxidizing environments.

Abstract: Preparation of amorphous semiconductor carbides that are suitable for use in a wide variety of devices by the pyrolytic decomposition of a mixture of one or more semiconductanes and one or more carbanes.

Abstract: Reaction-bonded silicon carbide artefacts are produced by siliconizing a green body formed from a coherent mixture of silicon carbide and carbon powders. The surface of the green body is coated with a paste comprising silicon powder suspended in a carbonizable viscous medium which, on heating of the coating, is converted to an open cellular carbon structure and then, on siliconizing the green body, to a silicon carbide skeleton through which molten silicon is drawn.

Abstract: Finely divided, hydrogen-activated catalyst compositions comprising iron, silicon and carbon or iron and silicon that selectively convert gaseous mixtures of CO and H.sub.2, at a temperature of about 150.degree.-450.degree. C. and at pressures of about 10-2000 kPa, into reaction mixture containing at least about 75% C.sub.2 -C.sub.6 alkenes and no more than about 25% of CH.sub.4 and undesirable CO.sub.2 by-products are disclosed. A wide range of iron/silicon-based catalyst compositions are conveniently prepared by laser pyrolysis and hydrogen-pretreatment and readily reactivated with hydrogen at elevated temperatures.

Abstract: In order to prevent a protective carbide layer on a graphitic molded article from splitting off under thermal stress, an external carbide layer is provided on a graphitic molded article having a graded content of silicon or zirconium (in the carbide state) that increases from near zero at the interior boundary of the layer to about 50 atomic percent at the exterior. Such a layer is produced either by dipping the graphitic molded article into melted silicon, dipping it into a succession of suspensions of carbon and either silicon or zirconium, with a greater silicon or zirconium content in each successive dip, the suspensions also including a binder resin, or by applying layers of a paste of carbon and either silicon or zirconium, also with some resin, each successive layer having a higher silicon or zirconium content.

Abstract: The present invention is directed to silicon carbide whisker recovery from a mixture of silicon carbide whiskers and carbonaceous silicon carbide particles. The invention involves shredding the mixture down to a specified size, dispersing the mixture in water to form an aqueous mixture, agitating the aqueous mixture, mixing the aqueous mixture with an immiscible organic solvent which is lighter than water, agitating the resulting water-organic solvent mixture, allowing the organic solvent and its contents to rise above the water and its contents, separating the two liquid phases into an organic solvent phase and an aqueous phase and, lastly, performing a solid-liquid separation on each of the two phases, thereby obtaining from the aqueous solution the desired silicon carbide whiskers and obtaining from the organic solvent solution a carbonaceous silicon carbide particle product.

Abstract: A plasma-arc process is disclosed for the production of powders of various chemical products, according to endothermic reactions, such as TiC and the like. The process consists essentially in carrying out, in a furnace with an anodic function without dissipative cooling, a series of steps comprising:(a) forming a chemically reactive fluidodynamic mass having a high thermal content and a high concentration of the desired reactive species, by injecting into the electronic column of a plasma-arc of a noble gas at least one reactant selected from the class consisting of metal and metalloid halides, the injection taking place, with mixing through a choker-injector-mixer nozzle which is electrically insulated;(b) causing the electronic condensation of said mass inside a main nozzle anode without dissipative cooling; and(c) injecting into said electronically condensed mass the residual part of said reactants necessary to the desired main chemical reaction for producing the chemical powder.

Abstract: A metal processing furnace of the indirect arc type having opposed electrodes projected into and establishing an ionized atmosphere in the furnace crucible is provided with apparatus that introduces a finely divided charge mixture consisting essentially of silica and coke into the system for free-fall into and through the ionized atmosphere. Following reaction of the mixture's ingredients in the ionized atmosphere, silicon carbide crystals are deposited at the bottom of the furnace interior below the ionized atmosphere for subsequent collection and removal from within the furnace system. By control of charge composition and process parameters, silicon carbide crystals having predominantly either alpha or beta crystalline structures and with crystal sizes predominantly in the range of 250 to 3,000 microns are produced.

Abstract: Shaped silicon carbide ceramic articles of high density, e.g., at least 90 percent of theoretical, are produced by cold pressing and sintering boron-containing high purity, submicron beta silicon carbide powder. The silicon carbide powder is produced preferably by gas phase reaction of silicon halide, e.g., silicon tetrachloride, carbon source reactant, e.g., halogenated hydrocarbon, and boron source reactant, e.g., boron trichloride, with a hydrogen plasma.

Abstract: A powder containing substantial amounts of alpha phase silicon carbide suitable for use in subsequent sintering operations to obtain a high-density, high-strength ceramic product is described. The powder may consist substantially entirely of alpha silicon carbide or may consist of mixtures of alpha and beta phase silicon carbide. The silicon carbide powder of the present invention has an average particle size of from about 0.10 to about 2.50 microns and may contain maximum amounts of the following materials by weight based upon 100 parts of powder.______________________________________ SiO.sub.2 2.00 Free Silicon 0.25 Iron 0.50 Alkali and Alkaline Earth Metals 0.50 Total Metal Oxides 3.75 ______________________________________Sinterable powders and methods of producing sintered products from the powders are also described.

Abstract: A process for removing silicon from a silicate-bearing material. The silicate-bearing material is analyzed for its silicon content and mixed with a controlled quantity of carbon as indicated by the analysis. The carbon is limited to an amount less than the stoichiometric amount necessary to react with the silicon to form silicon carbide. The silicate-bearing material/carbon mixture is formed into a first phase and interposed with a second phase containing additional carbon to form a reaction mixture. The reaction mixture is subjected to a carbothermal reduction reaction to reduce silica in the silicate-bearing material to silicon monoxide. At the temperatures involved in the reaction, the silicon monoxide is in the gaseous phase and readily diffuses from the first phase into the second phase where the diffused silicon monoxide reacts with the additional carbon in the second phase to form silicon carbide.

Abstract: A thin film of substantially defect-free pyrolytic graphite, useful as a bi-directional reinforcing material, is formed by vapor deposition on an inert liquid substrate surface and separated therefrom. The substrate temperature is substantially below the melting point of the refractory material and the substrate surface is smooth and free of stress to enable formation of a substantially defect-free film. Thin films of other refractory materials can be made similarly by first forming a pyrolytic graphite film on the substrate, and then vapor depositing a film of refractory material on the pyrolytic graphite surface. The pyrolytic graphite and refractory material films are then separated from the substrate surface and then separated from each other. Various refractory film materials can be made including pyrolytic grahite; boron; silicon; and refractory carbides, borides and nitrides. For making pyrolytic graphite films, it is preferable to use tin as the ubstrate, at a temperature of about 1600-1800.degree. C.

Abstract: A method of forming a silicon carbide article is disclosed. Selected weight percentages of silicon carbide particles, graphite particles, if desired, and a thermosetting binder are mixed together and molded into an article by molding techniques which operates on the basis that the thermosetting binder forms a continuous medium about all the particles supported therein. The molded article is heated in the absence of oxygen and the thermosetting binder breaks down to form a low density, vitreous carbon phase. The article is heated in an oxygen containing environment to remove excess surface carbon. The article is silicided at an elevated temperature by penetration of the article through its pore structure with a reactable form of silicon.

Abstract: A method for making said rigid pyrolytic graphite article comprising winding a continuous, individual, refractory filament or strand around a shaped form and simultaneously pyrolyzing a mixture of methyl trichlorosilane and a hydrocarbon gas onto the filament or strand at about the point of winding contact to nucleate pyrolytic graphite and SiC from the filament or strand, winding additional turns of the filament or strand around the form, each additional turn being spaced from previously wound turns and, as each of the additional turns is wound, simultaneously pyrolyzing the mixture of methyl trichlorosilane and hydrocarbon gas thereon at about the point of winding contact and on the codeposited pyrolytic graphite and SiC nucleated from previously wound turns.

Abstract: Silicon carbide articles are formed by wet milling a mixture of silicon carbide having an average particle size less than 10 microns, and colloidal graphite; eliminating powder agglomerates larger than 325 mesh (U.S. Standard Sieve Series); drying the milled powder and pressing it to the desired shape; and finally, firing the preform at approximately 2000.degree. C. in the presence of silicon, converting the graphite to silicon carbide.

Abstract: A method of growing silicon carbide whiskers from a gaseous phase by means of a vapor-liquid-solid mechanism on a substrate using iron in a finely divided state as a solvent for the silicon carbide.

Abstract: The preparation of metal and metalloid carbides, borides, nitrides silicides and sulfides by reaction in the vapor phase of the corresponding vaporous metal halide, e.g., metal chloride, with a source of carbon, boron, nitrogen, silicon or sulfur respectively in a reactor is described. Reactants can be introduced into the reactor through a reactant inlet nozzle assembly. Inhibition and often substantial elimination of product growth on exposed surfaces of such assembly is accomplished by introducing the corresponding substantially anhydrous hydrogen halide, e.g., hydrogen chloride, into the principal reactant mixing zone.

Abstract: In a process for producing an epitaxial layer of hexagonal silicon carbide on a silicon monocrystal substrate by simultaneous reduction or thermal decomposition of a gas mixture containing silicon halides and organosilanes, or mixtures thereof, hydrocarbons, and H.sub.2 on said substrate, the improvement consisting of having water or a water-forming compound present in the gas mixture, which leads to especially pure silicon carbide, useful, e.g. as material for light emitting diodes.

Abstract: Sections are cut from a SiC platelet such that the sections have a-faces parallel to the c-axis of the SiC platelet. The sections serve as substrates for the growth of SiC layers by attaching the substrates to a body which is then placed in a chamber and the chamber evacuated. Hydrogen is then admitted, and the body on which the substrates are mounted is heated to produce a temperature profile such that the subsequent admission of a carbon containing chlorosilane gas or a mixture of a chlorosilane gas and a hydrocarbon gas will cause free silicon to be deposited at one end of the body while SiC crystals grow on the substrates which are in a preferred temperature range. Dopant gases, either p-type or n-type, can be admitted with the chlorosilane or hydrocarbon gas to produce the desired type of semiconductor.